288 GRAMINE.K. Stipa. 



margins ; ligule very sliort, lacerate-fiiiigeil ; slicatlis somewhat loose, the uppermost 

 lunch dilated, striate, smooth except the margins, which are mostly ciliate, esitecially 

 at the throat : jiaiiicle 12 to IG inches long, at first spike-like anil included lor one- 

 third or one-hair its length, at length exserted and loose, hut narmw with erect 

 branches; lower rays in i)airs or threes, long and lluwer-heaiing above, the upper in 

 fascicled clusters and Hower-bearing to tiie base : 'spikelets «hortpeilicelleil, pale- 

 greenish becoming purplish : glumes uneipial, the 3-nerved lower about 8 lines, and 

 the 5-nerved ui)i)er G lines long, both acuniinato and somewhat bristle-pointed, 

 slightly scabrous on the nerves : floret, including the brief curved callus and long 

 hairy crown, 5 lines long ; lower palet scarcely cluutaceous, bilid with delicate hya- 

 line teeth less than a line long, clothed with silky shining hairs, those below about 

 a line long, the upper more numerous, forming a dense tufted corona 2 lines long; 

 awn about an inch long, sleiuler, bent mostly below the middle and minutely sca- 

 brous ; upper palet about half the length of the lower : stamens 3 ; anthers naked. 



Hills near Juliuu City, San Diego County (Bolandcr) ; near San Hernanlino, I'arry k Lcmvwn, 

 n. 422 (1876). The tallest and most robust of all North Anieiican Stii)as ; when young, with the 

 paniele partly inehuled, it appeals somewhat like ^'. Sti/lniani, but it lacks tlie marked and 

 peculiar lustre of that species. Later the j)anicle is exserted, becoming wider and loose and taking 

 on a purplish tinge, and the resemblance is no longer noticed. The reniaikably long hairs ujinn 

 the lloret have a peculiar silvery lustre ; when higldy magnified each hair is .seen to be flat and 

 spirally twisted. 



11. S. viridula, Trin. (^ulms l.l, to sometimes T) feet high, witli numerous 

 "withereil slu-aths at basi; : leaves all involute setaceous at apex, smooth or slightly 

 scabrous, pale green, the radical about one-third as long as the culm ; upper culm- 

 leaf 1 to l.V inches long ; ligule very short ; sheaths half the length of the internodes 

 or less : panicle G to 18 inches long, narrow, loose, the short erect rays in twos or 

 threes : spikelets 4 to 5 lines long, on shorter pedicels : glumes nearly e(pial, ovate, 

 bristle-pointed, the lower 5-, the ui)per 3-nerved, sometimes tinged with purjile : 

 lloret fusiform, about one-fourth shorter, the callus very short ; lower palet with 

 short scattered hairs which form a rather irregular crown and with 2 very minute 

 hyaline teeth ; upper palet more than half as long; awn 1 to U inches long, slender, 

 fiexuose, usually twice b(>nt, pubescent below and scabrous above, at length <ltH'.idu- 

 ous : anthers naked. — Act. Petroj^. 183G, 31) ; Trin. ct Kupr. Stipacea', 57 ; Watson, 

 ]>ot. King Exped. 380. S. parvi flora, iSutt. Geif. i. 58, not ])esf. S. qxirtni, 

 Hook. Fl. Bor.-Am. ii. 237, not Trin. 



In the Coast Kangp.s and Sierra Nevada, northward to Oregon, the upper Missouri {(/ri/n) 

 and British .America. Very variable in tlie size of the culm and character of the jKUiicle, which 

 is usually .slender an<i loo.sely Howered, sometimes reduced to a mere raceme of a few l-liowcred 

 ray.s, and at the other extreme crowded and spike-like. The young states of this and ,S'. Siluricd 

 very closely resemble one another, but that has longer rays naked lielow, the lloret more cojiiously 

 silky and the anthers conspicuously beanled. The lower palet in S. viridula slightly projects 

 on each siile of the insertion of the awn, and when that at length falls the scar is oblicpie. The 

 floret in both sjiecies becomes fuscous at matuiity. 



26. ARISTIDA, Linn. Tkipm -awnko On.\ss. 

 Panicle racemose or s})ike-like, rarely spreading. Spikelets 1-flowered. Glumes 

 unequal, the lower shorter, membranaceous, sometimes with a bristle-like pt)int. 

 Floret oval or cylindrical, with an ol)conic mostly hairy callus ami readily falling at 

 maturity. Lower palet chartaceous or coriaceous, longer than and inclosing the 

 upper, entire at ajtex where it bears a three-parted awn, with or witliouta joint at its 

 base. Scales 2. Stamens 3; anthers beardless. Ovary stipitate : styles distinct. 

 Grain cylindrical, inclosed in the lower jialet, but free from it. 



Over L'JO species are enumeratetl, of which the laiger .share btdong to warm countries. Tin; 

 culujs, from an annual or perennial root, aie often much branched ; lln' leaves narrow and mostly 



